[PATCH 3.12 17/62] ARM: OMAPFB: panel-sony-acx565akm: fix bad unlock balance

Greg Kroah-Hartman
2013-12-10T08:20:26Z

From: Aaro Koskinen <aaro.koskinen@iki.fi>

commit c37dd677988ca50bc8bc60ab5ab053720583c168 upstream.

When booting Nokia N900 smartphone with v3.12 + omap2plus_defconfig
(LOCKDEP enabled) and CONFIG_DISPLAY_PANEL_SONY_ACX565AKM enabled,
the following BUG is seen during the boot:

[ 7.302154] =====================================
[ 7.307128] [ BUG: bad unlock balance detected! ]
[ 7.312103] 3.12.0-los.git-2093492-00120-g5e01dc7 #3 Not tainted
[ 7.318450] -------------------------------------
[ 7.323425] kworker/u2:1/12 is trying to release lock (&ddata->mutex) at:
[ 7.330657] [<c031b760>] acx565akm_enable+0x12c/0x18c
[ 7.335998] but there are no more locks to release!

Fix by removing double unlock and handling the locking completely inside
acx565akm_panel_power_on() when doing the power on.

Reported-by: Eduardo Valentin <eduardo.valentin@ti.com>
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/video/omap2/displays-new/panel-sony-acx565akm.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

--- a/drivers/video/omap2/displays-new/panel-sony-acx565akm.c
+++ b/drivers/video/omap2/displays-new/panel-sony-acx565akm.c
@@ -526,6 +526,8 @@ static int acx565akm_panel_power_on(stru
struct omap_dss_device *in = ddata->in;
int r;

+ mutex_lock(&ddata->mutex);
+
dev_dbg(&ddata->spi->dev, "%s\n", __func__);

in->ops.sdi->set_timings(in, &ddata->videomode);
@@ -614,10 +616,7 @@ static int acx565akm_enable(struct omap_
if (omapdss_device_is_enabled(dssdev))
return 0;

- mutex_lock(&ddata->mutex);
r = acx565akm_panel_power_on(dssdev);
- mutex_unlock(&ddata->mutex);
-
if (r)
return r;